Journal of Supercritical Fluids, Vol.143, 146-156, 2019
Polycaprolactone foams prepared by supercritical CO2 batch foaming of polymer/organic solvent solutions
In this work, the batch foaming of polymeric solutions by means of supercritical CO2 (scCO(2)) is described. The developed process combines the advantages of processing materials from solution in organic solvents and scCO(2) batch foaming to prepare foams with uniform and controllable porosity. Polycaprolactone (PCL) was selected as semi-crystalline polymer as a case study and foams from solutions in different scCO(2)-miscible organic solvents, namely ethyl acetate, chloroform, dioxane and dimethyl sulfoxide, were prepared. Obtained results demonstrate that processing PCL solutions by means of scCO(2) batch foaming enables preparing solid polymeric foams with solvent residue close to 1 wt. %, density values in the 0.2-0.5 g/cm(3) range, hundreds of microns pore size and pore walls with spherulitic morphology. The advantage of this process is herein demonstrated by the fabrication of composite PCL foams containing 30 w% of either inorganic TiO2 nanoparticles and 5-fluorouracil chemotherapeutic by processing polymeric solutions in a single step.